This invention relates to an electromagnetic relay which has a plurality of relay units, and more particularly to an electromagnetic relay which has a pair of normally closed and normally open terminals on which at least two fixed contacts are mounted.
When a d.c. motor is rotated in alternate directions, two electromagnetic relays are required: one is for the clockwise direction and the other for the counterclockwise. This is also true for the case in which a polar solenoid is activated in alternate directions.
Conventional electromagnetic relays, however are separated from each other. Therefore, each conventional electromagnetic relay independently requires its own wiring pattern to provide an electric circuit for operating motors or polar solenoids in alternate directions. This results in complicated wiring patterns on a printed circuit board and requires a very long time and high cost to design them.
In addition, these separated electromagnetic relays independently require an area to be electrically insulated from the other electric components on the circuit board. This causes a large area to be used and hinders designers from providing high-density circuits. Moreover, since the relays independently require their own components, they are expensive.